Garment and fabric processing today includes dyeing and desizing. Sizing is important in the fabric weaving and garment sewing processes. The size is usually removed in a finishing operation after the fabric is woven. In some fabrics e.g. Denim, the size is left in woven goods to give desirable properties to the denim garment so as to improve the wear properties of the fabrics or garments. However, if the garments or fabrics are further processed, for example, treated with a crosslinking agent and/or decolorized or finished in garment form, it is necessary to first remove the sizing.
The removal of sizing is today performed in most textile plants by one or more of the following methods. The primary method of desizing is enzymatically, for example utilizing amylolytic enzymes. In garment finishing this process is more costly. Mechanical action during garment desizing whereby abrasive drum linings in extractors and/or pumice stones are utilized to improve the garment softness and give the garment special features etc. Alkaline and acidic hydrolysis have also been employed but such techniques also cause chemical attack of the fabric so as to result in a loss of the tensile and tear strength of the fabric and/or garment. Oxidative desizing is generally employed using large amounts of sodium hypochlorite in solution. The use of hypochlorite creates environmental problems and further can significantly degrade the fabric. Desizing is required where the fabrics or garments are to undergo further processing such as dyeing, printing, decolorization, treatment with a crosslinker, ozone treatments and the like.
Garment dyeing technology, particularly with denim jeans, to achieve a differential color appearance has focused on treatments in which the dyer starts with a dyed garment and achieves a differential color effect by partial color removal. Removal of color is achieved by use of porous stones soaked in oxidizing agents, such as strong bleach or permanganates, and more recently, by after treatment with cellulose enzymes to remove fiber and thereby also remove some sizing.
U.S. Pat. No. 5,118,322 to Wasinger et al, which is incorporated herein by reference, relates to a process for decolorizing garments utilizing garments which are wetted and the garments are treated with ozone in combination with steam.
U.S. Pat. No. 4,283,251 in Singh discloses the bleaching of cellulosic pulp with gaseous ozone in an acidic pH followed by an alkaline treatment.
U.S. Pat. Nos. 4,214,330 and 4,200,367 to Thorsen, which are herewith incorporated by reference, describe a method and an apparatus for treatment of undyed fabrics with an ozone-steam mixture. The process is used to shrinkproof the fabric with a minimum amount of deterioration of the fabric fibers. The ozone treatment reacts with the undyed fibers and provides whiter fibers. The treatment is stated to increase subsequent dyeability and dye fastness of the garment.
W. J. Thorsen et al in their paper entitled, "Vapor-Phase Ozone Treatment of Wool Garments", Textile Research Journal, Textile Research Institute, 1979, pp. 190-197, describe the treatment of wool fabrics and garments with ozone and steam to provide shrink resistance to the fabric or garment. The process is based on the reaction of the ozone with the wool fibers.
It should be understood that the term "dye" as used herein is meant to include any of the materials which are used to provide a color to a fabric such as conventional dyes, pigments, or the like.
It should be understood that the term "ozone" as used herein denotes a preferable method of the invention and is meant to include ozone alone or ozone diluted with inert gases.